Tamper-proof envelope



M. RIBACOFF TAMPER-PROOF ENVELOPE Filed June 2, 1954 IN V EN TOR.

Mafia Ralbacqyff United States Patent TAMPER-PROOF ENVELOPE Mark Ribacotf, New York, N. Y.

Application June 2, 1954, Serial No. 433,992

1 Claim. (Cl. 229-450) This invention relates to the art of envelopes, more particularly of the tamper-proof type.

As conducive to an understanding of the invention, it is noted that mailing envelopes generally have an exposed flap which is sealed to close the envelope and which may readily be steamed open without injury to the envelope, and the contents removed.

This is highly undesirable, especially when the envelopes are used for registered mail, for governmental and diplomatic use and for use by the armed services and by banks.

It is accordingly among the objects of the invention to provide an envelope that may be fabricated at relatively low cost from a sheet of paper and which, when sealed, will have no exposed flaps which may be steamed open for ready removal of the contents of the envelope, without injury to the envelope that may be readily detected, thereby resulting in a substantially tamper-proof envelope.

According to the invention from its broader aspects, the mouth of the envelope is closed by a tuck-in flap which is gummed on both sides so that it will adhere to both walls of the envelope at its month.

More particularly, where the envelope is formed in such manner that the end opposite its mouth must also be sealed during the fabrication of. the envelope, then both the front and back panel of the envelope are desirably formed with inturned flaps which are gummed on both sides so that they will adhere to the inner faces of the panels as well as to themselves.

In the accompanying drawings in which are shown one or more of various possible embodiments of the several features of the invention,

Fig. 1 is a plan view of the blank from which the envelope is formed,

Figs. 2 and 3 are views of the blank during various steps of forming the envelope, and

Fig. 4 is a perspective view of the completed envelope.

Referring now to Fig. 1 of the drawings, the blank B desirably comprises a rectangular center panel 11 which forms the front wall of the envelope and two lateral panels 12 and 13 which form the back wall of the envelope.

The center panel 11 has two end flaps 14 and 15 and the lateral panels 12 and 13 have end flaps 16, 17 and 18, 19 respectively.

As is clearly shown in the drawings, both faces of each of the flaps 14- to 19 inclusive are gummed on both sides with any suitable adhesive and the inner longitudinal edge 21 of panel 13 and the outer longitudinal edge 22 of panel 12 are also gummed.

To form the envelope, the flaps 15, 16, 17, 18 and 19 are all turned inwardly as shown in Fig. 2, so that their gummed surfaces will adhere to the adjacent surface of the associated panel.

The lateral panels 12 and 13 are thenv turned inwardly over the center panel 11 as shown in Fig. 3 with the edge 21 overlapping the edge 22 to form the back wall.

At this stage of formation of the envelope, the gummed flap 15 will adhere to the gummed flaps 17 and 19 so that the closed end of the envelope will comprise four thicknesses of material, i. e., panel 11, flaps 15, 17 and 19 and panels 12 and 13. In addition, the gummed edge 21 of panel 13 will adhere to the gummed edge 22 of panel 12 which it overlaps. If desired, the adjacent ends 23, 24 of flaps 16, 18 and 17, 19 can be interleaved for added adherence.

The envelope as thus formed is now ready to receive a letter, or other contents. After such contents are inserted into the open mouth of the envelope, the gummed flap 14 is turned into such month so that it will adhere both to the adjacent surface of the center panel 11 and to the flaps 16 and 18.

It is apparent from the foregoing that the envelope when thus sealed will have no exposed closure flaps which may be directly subjected to steam for opening and it is diflicult if not impossible to open the envelope and remove its contents except by tearing or cutting such envelope which would leave a visual indication that the envelope had been tampered with.

The expression gummed when used herein is intended to include material which becomes adhesive when wet or which becomes adhesive under the application of pres sure.

As many changes could be made in the above construction, and many apparently widely different embodiments of this invention could be made without departing from the scope of the claim, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of he United States is:

A tamper-proof envelope comprising a rectangular front wall having an inturned flap at one end aifixed to the inner adjacent end of said front wall, and another flap at its other end gummed on both surfaces, a rectangular back wall comprising two panels each having one of their longitudinal edges formed integral with the respective longitudinal edges of said front wall, said panels extending over said front wall, each of said panels having an inturned flap at one end atfixed to the adjacent wall of the associated panel and to the inturned flap at the end of said front wall, said panels also having inturned flaps at the other end thereof adjacent the said other gummed flap of said front wall, said last mentioned inturned flaps being aflixed to the inner surface of the adjacent end of the associated panel and being gummed on the other surface thereof.

References Cited in the file of this patent UNITED STATES PATENTS 602,411 Sigesmond Apr. 12, 1898 1,127,703 Van Ripper Feb. 9, 1915 1,141,603 Beltramini June 1, 1915 1,196,245 Knurch Aug. 29, 1916 1,344,071 Webster June 22, 1920 1,363,252 James Dec. 28, 1920 2,366,575 Teicher Jan. 2, 1945 

